DE1241796B - Process for the production of briquette binders - Google Patents

Description

Process for making briquette binders The invention relates to a process for the production of binders from a coal tar pitch and an aromatic compound that burns smoke-free and soot-free, for briquetting of fuels. Such binders and processes for their production are known, however, they have the disadvantage that the production is relatively complicated thereby because a special pitch must be used and because a requirement is the use a coal to be briquetted with a certain moisture content.

The invention avoids these disadvantages by using a normal untreated briquette pitch, the binder for both moist and for dry fuel is usable.

Compared to known processes in which coal tar pitch as a binder is used (briquette pitch), especially with certain types of coal the Briquettes to smoke.

To reduce the build-up of smoke from coal tar pitch Several proposals have already been made for bound briquettes. So it was proposed to treat the briquettes thermally after molding and with or without anoxidation to smolder. This results in semi-coke-like burning practically smokeless and sootless Briquettes. The method has the disadvantage of high additional costs.

It has also been suggested to reduce smoke build-up other binders, such as B. petroleum bitumen to use; yet have these suggestions in practice because of the unsuitability of the substitute products as briquette binders generally not be able to enforce. Quite apart from the operational difficulties, the z. B. the use of bitumen because of its flat temperature viscosity curve brings with it, bitumen briquettes are too plastic and show insufficient stability in the fire.

According to the invention the binder will now be smoke and soot-free burning produced from a coal tar pitch in that Brikettpech with aromatics cracking residues or distillation residues from aromatenreichem oil having a hydrogen content above 7% and a softening point according to K r ä me r- S Arnow 20-751 C in amounts of 3 to 25 % and optionally inorganic additives such as manganese, nickel or calcium compounds or phosphates or mixtures of these substances, in amounts of 1 to 5 % or up to 7% in the case of calcium compounds for the purpose of lowering and practically collapsing the flash point and the focal point of the mixture is displaced.

According to a preferred embodiment, the inorganic additives of the mixture of briquette pitch and aromatics-containing cracking residues or distillation residues from aromatics-rich petroleum in dry, pulverized form are added or mixed into the melted binder at temperatures above 80 ° C. or the ground coal-binder mixture before briquetting . This surprisingly makes it possible to significantly reduce the development of smoke and soot, and this effect is based on the fact that both the flash point and, to an even greater extent, the fire point of the binder mixture are lowered by the additives, in such a way that the flash point and fire point are practically coincide, thereby preventing unburned distillates from escaping when the pitch is heated. These unburned distillates are the main causes of smoking.

The graphs (Fig. 1 and 2) illustrate the effect of increasing the addition of aromatic and el-containing cracking residues or of inorganic additives on the time from the start of the melting point for the binder mixture to the point at which the flash point or fire point occurs. While the curves in Fig. 1 show that without such an addition or with small amounts of added cracking residues, the focal point (curve 1) and flash point (curve 2) are apart, with the addition of about 15 % cracking residues from the curves initially approach until they converge and at larger additions coincide to form a curve, the curves in Fig. 7 show the course of the change in the focal points of briquette pitch with 5% crack residues each and varied additions of manganese dioxide and / or lime sludge according to a preferred embodiment of the invention.

The curve 1 in Ab b. 2 illustrates the effect of increasing additions of lime sludge on the fire point of a briquette pitch-cracked residue mixture (with 5 % residues) and curve 2 the effect of additions of brownstone on the fire point of such a mixture, while curve 3 shows the course of the reduction in the Focus and the approximation to the flash point curve when adding a mixture of lime sludge and manganese dioxide - in equal parts - to the above-mentioned pitch-residue mixture shows (in comparison with curve 4, the flash point curve of the binder mixture, as it was used to establish curve 3 ).

The inorganic additives to the mixtures of briquette pitch and hydrogen-rich residues containing aromatics amount to about 1 to 5 %, namely manganese compounds, e.g. B. technical manganese dioxide or manganese naphthenate, and / or nickel compounds, z. B. nickel oxide or nickel naphthenate, and / or 1 to 7% calcium compounds, e.g. B. calcium carbonate, or the resulting from the extraction of crude phenol from coal tar dried lime sludge (calcium carbonate with minor impurities of calcium hydroxide), and / or phosphates, z. B. the waste phosphate resulting from the production of sodium phosphate, which contains, among other things, sodium, calcium, barium and iron as cations, or technical sodium phosphate or other metal phosphates.

The additives can optionally be added to the briquette pitch without prior Admixture of the aromatic, hydrogen-rich residues can be added.

The organic and inorganic additives, in addition to reducing the flash point and fire point, cause a skin to form towards the end of the combustion, which means that the flame-retardant, high-molecular-weight distillation gases are held together under the skin until they have cracked into low-molecular proportions, which burn easily and do not form smoke. In addition, as a result of the better combustion - probably due to the catalytic effects of the inorganic additives - a significant reduction in soot formation can be observed.

The addition of calcium compounds also binds the sulfur and an improvement in the binder properties of the pitch.

The additives are added in the heat while stirring the melted briquette pitch, the organic additives expediently also being melted beforehand. The inorganic additives pulverized prior to admixture can optionally also be added to the briquetting material, i.e. H. the mixture of coal and pitch, if the briquetting is not carried out by a process in which liquid pitch is used.

The assessment of the quality of the binders with and without additives is expediently carried out in a burning test in which 5 g of the binder are slowly heated from below on an iron dish with a constantly burning gas flame. The time taken to reach the flash point, to the focal point and to the extinction of the flame is measured and the phenomena that occur, such as smoke development, soot deposition, skin formation and coke formation, are observed.

In this experiment, normal briquette pitch develops a considerable amount of yellow to brown-red vapors between flash point and fire point, which are difficult to ignite. When the pitch is subsequently burned off, thick plumes of soot are created and - if the flame goes out at the end of the burning process - the half-coked residue releases clouds of yellow smoke for a long time, which can hardly be made to burn. A pitch treated according to the invention, on the other hand, burns off largely free of smoke and soot. Example 1 85 parts of normal Brikettpech (EP 69.50 C S. K.) and 15 parts aromatic-containing residue with a hydrogen content of 7.80 / 0 are mixed at temperatures above 80 "C. The mixture is compared to normal Brikettpech when Abbrennversuch a reduction in the flash point and an almost instantaneous continued burning (ie a cooperation fall of flash and fire points) virtually without smoke development. At the end of the burning process, the mixture soon forms a firm skin of coked material, which puffs up and under which the distillable components crack or coke, so that the vapors then escaping when the bubbles burst are easily flammable gases that do not develop any smoke. Example 2 In a mixture of 89 parts of normal briquette pitch (EP 69.50 C K. S.) and 5 parts of aromatic-containing residue with a hydrogen content of 8.1 "10, 2 parts of technical manganese dioxide and 2 parts of dried lime sludge are formed at over 80 ° C. the coal tar phenol and 2 parts of technical sodium phosphate stirred.

The binder mixture burns practically smoke-free and largely free of soot away.

Claims (2)

Claims: 1. A process for the production of smoke-free and soot-free burning binders from a coal tar pitch and an aromatic compound for briquetting fuels, d a - characterized in that briquette pitch with aromatics-containing cracking residues or distillation residues from aromatic-rich crude oil with a hydrogen content above 71 / o and one Softening point according to Krämer-Sarn ow between 20 and 751 C in amounts of 3 to 25% and optionally inorganic additives such as manganese, nickel or calcium compounds or phosphates or mixtures of these substances in amounts of 1 to 5 % or 1 to 7 % is added in the case of Caleiumverbindungen for the purpose of lowering and practically coinciding the flash point and fire point of the mixture. 2. The method according to claim 1, characterized in that the inorganic additives of the mixture of briquette pitch and aromatic-containing crack residues or distillation residues from aromatic-rich petroleum in dry, powdered form in the melted binder at temperatures above 801 C or the ground coal-binder mixture before Briquetting can be stirred in or mixed in. Considered publications: German Patent Specifications Nos. 958 554, 433 734; German Auslegeschrift No. 1 011851; Austrian Patent No. 3696; French patent specification No. 378 110.